CN104204043B

CN104204043B - Capacitor biaxial-stretched polypropylene films, metalized film and membrane capacitance

Info

Publication number: CN104204043B
Application number: CN201380016476.8A
Authority: CN
Inventors: 中冢贵典; 浅野哲也; 菅田正美
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2012-03-28
Filing date: 2013-03-15
Publication date: 2017-11-21
Anticipated expiration: 2033-03-15
Also published as: WO2013146367A1; JPWO2013146367A1; EP2832776A1; US20150050456A1; KR102044577B1; EP2832776B1; JP6120180B2; CN104204043A; EP2832776A4; US9805868B2; KR20140143185A

Abstract

The problem of the present invention is to provide a kind of capacitor biaxial-stretched polypropylene films, it is the capacitor biaxial-stretched polypropylene films that two sides has projection, thickness t1 (μm) is 1~3 μm, one film surface is being set to A faces, when another side is set into B faces, meet whole following formula (1)~(4).The present invention provides and excellent proof voltage, safety guarantee, reliability is played in high-voltage electrical container application, in addition and ensures biaxial-stretched polypropylene films, metalized film and the membrane capacitance of stable element processability.|Pa‑Pb|≥200···(1)；0.350≤Pa/SRzA≤0.700···(2)；500nm≤SRzA≤1,200nm···(3)；50nm≤SRzB ＜ 500nm (4)；Wherein, Pa represents A faces per 0.1mm²The number of existing projection, Pb represent B faces per 0.1mm²The number of existing projection, SRzA represent 10 mean roughness in A faces, and SRzB represents 10 mean roughness in B faces.

Description

Capacitor biaxial-stretched polypropylene films, metalized film and membrane capacitance

Technical field

The present invention relates to be suitable for being packed for, industrial etc. biaxial-stretched polypropylene films, say, be related in further detail As capacitor dielectric high proof voltage, the biaxial-stretched polypropylene films of suitable element excellent in workability, and make With the metalized film and membrane capacitance of the biaxial-stretched polypropylene films.

Background technology

The transparencys of biaxial-stretched polypropylene films, mechanical property, electrical characteristic etc. are excellent, therefore are used in packaging applicationss, band On the way, using cable bag cicada, capacitor as various uses such as the electrical applications of representative in use.

Wherein, it is special due to its excellent voltage-resistent characteristic, low loss on capacitor purposes, biaxial-stretched polypropylene films Property, therefore direct current purposes, exchange purposes are not limited to, used particularly preferred for high voltage capacitor.

Recently, various electrical equipments accompany by inverter control with this, miniaturization, Large Copacity for capacitor The requirement of change further enhances.By the requirement in such market, particularly mobile applications (including hybrid electric vehicle purposes), make The proof voltage of biaxial-stretched polypropylene films, safety guarantee (self-healing property), element processability improve, while more film film It is melted into as necessary situation.

Such biaxial-stretched polypropylene films, from the viewpoint of proof voltage, safety guarantee, element processability, need Surface is moderately roughened, and this is assigned especially for the sliding of film, the raising of oily impregnation or to evaporation capacitor Safety guarantee is especially important.Here, so-called safety guarantee, it is the metal deposition film formed on the dielectric film As in the metal evaporation capacitor of electrode, in paradoxical discharge, evaporation metal is dispersed due to discharge energy, so that insulation Property recover, short circuit is prevented, so as to maintain the function of capacitor or prevent the function of capacitor breakdown, from the aspect of security And exceedingly useful function.

As such roughened method, the mechanical means such as embossing method, sand-blast are proposed so far, utilize solvent The chemical methodes such as chemical etching, the method that the piece of the dissimilar polymers such as polyethylene is stretched is blended with, β crystalline substances will be generated Method (see, for example patent document 1,2) that piece is stretched etc..

However, in mechanical means and chemical method, roughness density step-down, it will generate what the brilliant pieces of β were stretched In method, it is prone to thick projection, therefore at aspect as roughness density, thick projection, projection number, sometimes can be with Say and be not necessarily sufficiently.In addition, roughened film has been carried out using these methods, the oil when capacitor is formed between film layer Impregnation becomes insufficient, is easy to generation and is not partly impregnated with part, capacitor life-span reduces sometimes.It is in addition, poly- that will be combined with In the method that the piece of the dissimilar polymers such as ethene is stretched, the remaining of bubble is lacked when capacitor is formed, but is carried out by the film In the case of recycling, dissimilar polymer brings harmful effect sometimes, there is the problem of recycling property difference is such.

In addition, the biaxial-stretched polypropylene films obtained by either method, are as more than 400V/ μm in electric potential gradient Under the very strict use condition of capacitor, proof voltage and safety guarantee are all insufficient, sometimes in reliability, life-span side Face produces problem.Here so-called electric potential gradient, it is every for value obtained by putting on the voltage divided by the film thickness of dielectric film The application voltage of unit film thickness.

On the other hand, on roughness density, the uniformity of projection, it is proposed that melt the polyacrylic film of tension force added with height (see, for example patent document 3,4,5).Wherein, in patent document 3,4, on roughness density, the uniformity of projection, although seeing Effect has been arrived, but still can not closely control the rising height in film table, required by particularly can not fully meeting mobile applications High proof voltage and safety guarantee, the whole of element processability.

In addition, Patent Document 5 discloses the biaxial-stretched polypropylene films of the roughened degree in control film table and its manufacture Method.However, the technology of patent document 5 is using thicker film as object, for the thin of the film as the purpose of the present invention For membranization, difficulty is applicable, it is in the present invention as to the film like that for fully meeting high proof voltage not to be in addition.This Outside, for film two sides is imperceptibly roughened, and for controlling the rising height in film table, this method is insufficient, is Difficult.

In addition, the patent document 6,7 of the roughness on film surface on defining at least one side, fine thick as being formed The method in face, by making the β crystalline substance point rates of casting blank sheet in prescribed limit, so as to so that element it is windability with it is pressure-resistant mild-natured Weighing apparatus.However, the manufacture method can not fully control the roughened degree on film two sides, and the fine asperities degree of the film of gained can not Fully meet the high proof voltage and safety guarantee, the whole of element processability particularly required by mobile applications.

Prior art literature

Patent document

Patent document 1：Japanese Unexamined Patent Application 51-63500 publications

Patent document 2：Japanese Unexamined Patent Publication 2001-324607 publications

Patent document 3：Japanese Unexamined Patent Publication 2011-122143 publications

Patent document 4：International Publication WO2012/002123 publications

Patent document 5：Japanese Unexamined Patent Publication 2011-122142 publications

Patent document 6：Japanese Unexamined Patent Publication 2007-308604 publications

Patent document 7：Japanese Unexamined Patent Publication 2008-133446 publications

The content of the invention

Invent problem to be solved

The present inventor etc. have made intensive studies to solve above-mentioned problem, as a result contemplate the present invention.The present invention carries For particularly excellent proof voltage and safety guarantee, reliability are played in high-voltage electrical container application, in addition and Ensure biaxial-stretched polypropylene films, metalized film and the membrane capacitance of stable element processability.

For solving the method for problem

The present invention for solving above-mentioned problem has following characteristics.

(1) a kind of capacitor biaxial-stretched polypropylene films, it is that two sides has the capacitor of projection with biaxial stretch-formed poly- third Alkene film, thickness t1 (μm) is 1~3 μm, and a film surface is being set into A faces, when another side is set into B faces, is meeting whole following formula (1)~(4).

|Pa-Pb|≥200 ···(1)

0.350≤Pa/SRzA≤0.700 ···(2)

500nm≤SRzA≤1,200nm ···(3)

50nm≤SRzB ＜ 500nm (4)

In above-mentioned formula (1)~(4), Pa represents A faces per 0.1mm²The number of existing projection, Pb represent B faces per 0.1mm² The number of existing projection.SRzA represents 10 mean roughness in A faces, and SRzB represents 10 mean roughness in B faces.

(2) the capacitor biaxial-stretched polypropylene films according to above-mentioned (1), the center line average roughness in A faces (SRaA) it is more than 25nm and below 45nm.

(3) the capacitor biaxial-stretched polypropylene films according to above-mentioned (1) or (2), the center line average roughness in B faces It is more than 10nm and below 25nm to spend (SRaB).

(4) a kind of metalized film, the capacitor biaxial stretch-formed polypropylene described in its any one in above-mentioned (1)~(3) At least one side of film is provided with metal film.

(5) metalized film according to above-mentioned (4), the sheet resistance of metal film is 1~20 Ω/.

(6) a kind of membrane capacitance, the metalized film described in above-mentioned (4) or (5) is it used.

The effect of invention

According to the present invention it is possible to provide by with excellent surface characteristic, even if so as to being thin film, flexibility (adaptability) of operation Also it is excellent, also play high proof voltage under the conditions of the atmosphere temperature of the wide scope of low temperature (- 40 DEG C) to high temperature (115 DEG C) Capacitor biaxial-stretched polypropylene films, be therefore particularly suited for capacitor purposes, preferably automobile using.

Embodiment

Hereinafter, capacitor biaxial-stretched polypropylene films and metalized film, the film being related to one embodiment of the present invention Capacitor illustrates in more detail.

The biaxial-stretched polypropylene films of present embodiment have projection on two sides, and thickness t1 is 1 μm~3 μm.In addition, on Its thickness, as described later, for the thickness obtained by micrometer method.In addition, it is characterised in that a film surface is being set to A faces, When another side is set into B faces, meet whole following formula (1)~(4).

|Pa-Pb|≥200 ···(1)

0.350≤Pa/SRzA≤0.700 ···(2)

500nm≤SRzA≤1,200nm ···(3)

50nm≤SRzB ＜ 500nm (4)

First, thickness t1 is illustrated.On the capacitor biaxial-stretched polypropylene films of present embodiment, from electric capacity Set out in terms of device component size and film stability, the film thickness (t1) obtained by micrometer method is preferably 1~3 μm.Pass through The film thickness that micrometer method obtains is more preferably 1.2~2.5 μm, particularly preferably 1.5~2.3 μm.If the thickness of film is less than 1 μm, then mechanical strength, dielectric breakdown strength, proof voltage are poor sometimes.In addition, if the thickness of film is more than 3 μm, as electricity Container it is dielectric in the case of, the capacity of unit volume diminishes, and becomes to be unfavorable for capacitor miniaturization, lightweight sometimes.

In addition, the film of present embodiment meets with following formula (1), (2).

|Pa-Pb|≥200 ···(1)

0.350≤Pa/SRzA≤0.700 ···(2)

In above-mentioned formula (1), (2), Pa represents A faces per 0.1mm²The number of existing projection, Pb represent B faces per 0.1mm² The number of existing projection.SRzA represents 10 mean roughness in A faces.

If | Pa-Pb | value be more than 200, the disparity surface on two sides further expands, and can be formed in capacitor When film interlayer spacings in keep appropriate air layer.Thus paying attention to as the safety guarantee of capacitor, self-healing property (from extensive Multiple technique), in the purposes of reliability, can particularly maintain optimal film interlayer spacings, capacitor specific characteristics become good.This Outside, if Pa/SRzA is less than more than 0.350 0.700 in (2) formula, projection density is high, forms uniform projection, therefore Self-healing property becomes good.

In addition, the film of present embodiment, as described above shown in (3) formula, 10 mean roughness (SRzA) in A faces are 500nm Below above 1,200nm.If 10 mean roughness (SRzA) are less than 500nm, due to be vented it is bad and can not be smooth The winding of film is carried out, in addition in evaporation process, cutting action and capacitor element volume process, is easy to injured when having conveying, into For the tendency of defect.Particularly, in capacitor element rolls up process, fold is easily formed, interlayer spacings are also narrow, occur local Interlayer it is closely sealed, pressure-resistant be easy to reduce because electric field is concentrated.In addition, in the case of more than 1,200nm, due to thick projection And it is prone to the reduction of insulation breakdown, film minimum thickness diminishes, therefore proof voltage is poor sometimes.

In addition, the film of present embodiment, as described above shown in (4) formula, 10 mean roughness (SRzB) in B faces for 50nm with Go up and be less than 500nm.If 10 mean roughness (SRzB) are less than 50nm, can not smoothly enter because sliding deteriorates The winding of row film, in addition in evaporation process, cutting action and capacitor element volume process, it is easy to injured when having conveying, turns into The tendency of defect.In addition, in the case of more than 500nm, film interlayer spacings broaden, it is prone to the reduction of insulation breakdown, film Minimum thickness diminishes, therefore proof voltage is poor sometimes.

In addition, in the case where SRaA is more than 25nm below 45nm, self-healing property improves sometimes.In addition, it is in SRaB In the case of more than 10nm below 25nm, proof voltage becomes good sometimes.

Here, the technical background of the present invention is illustrated.In order that the proof voltage of polypropylene screen, safety guarantee, Self-healing property, element processability are good, and surface roughness, rising height, the projection number on control polypropylene screen two sides are important. In addition, the uniformity of film interlayer spacings, the size in gap, projection density, film are each other or the slip easiness of film and conveying roller is It is important, it is desirable to reduce and the closely sealed mutual local interlayer of film in the case of element, dustability of evaporation metal, remnants are made Stress is simultaneously optimized.Therefore, in the present invention, use only with conventional two-dimentional or three-dimensional center line surface roughness, The index that 10 mean roughness can not show.That is, more than 500nm 1 is in for SRzA, below 200nm, SRzB are in 50nm Less than the film of 500nm scope, by further by the norm controlling related to projection number in appropriate scope, So as to obtain suitable element processability and high proof voltage, safety guarantee, self-healing property.

If in general, make smooth surface to carry out high proof voltage, although film minimum thickness is thickening, resistance to electricity Pressure property improves, but gap turn narrow between film layer, and because the adaptation of evaporation metal and film improves, so as to have safety guarantee, The tendency that self-healing deteriorates.

In the present invention, a film surface is being set to A faces, when another side is set into B faces, 10 mean roughness in A faces (SRzA) it is more than 500nm 1, below 200nm, 10 mean roughness (SRzB) in B faces are 50nm less than 500nm, And meet whole following formula (1), (2), although so as to be that film thickness is 1~3 μm of very thin film, can have concurrently Required high proof voltage and safety guarantee, self-healing property.

|Pa-Pb|≥200 ···(1)

0.350≤Pa/SRzA≤0.700 ···(2)

In addition, the biaxial-stretched polypropylene films of present embodiment, the center line average roughness (SRaA) in A faces are preferably More than 25nm below 45nm.If SRa is less than 25nm, sometimes due to be vented bad grade and the winding of film can not be smoothed out, Confusion occurs, it is impossible to successfully carry out cutting action, capacitor element is formed roll-shape.In addition, sometimes film lamination when layer Between gap turn narrow, self-healing property reduce.On the other hand, in the case where SRaA is more than 45nm, breakdown voltage is likely to decrease, SRaA is preferably 25nm~45nm.SRaA is more preferably 26nm~40nm, particularly preferably 28nm~35nm, thus, it is possible to obtain Safety guarantee, self-healing property are good, the film of excellent in workability.

In addition, the biaxial-stretched polypropylene films of present embodiment, the center line average roughness (SRaB) in B faces are preferably More than 10nm below 25nm.If center line average roughness (SRaB) is more than 25nm, in the case of by film lamination, air Interlayer is easily entered, occasionally results in the deterioration of capacitor element.If opposite SRaB is less than 10nm, the slip of film reduces, behaviour The property made is poor, or in the case where insulating oil is impregnated in into capacitor element, insulating oil is not infiltrated between film layer equably sometimes, even Volume change becomes big during continuous use.SRaB is more preferably 15nm~23nm, particularly preferably 17nm~22nm, it is possible thereby to obtain The film of high proof voltage and excellent in workability.

It is respectively above range by the center line average roughness (SRaA, SRaB) for the one side for making film, so as to enter Windability, when being made capacitor the volume change that one step is obtained in capacitor element formation process is small, it can be ensured that high proof voltage Property, improve the excellent film of safety guarantee.

The double of defined present embodiment have been carried out as described previously for protrusion of surface height, projection density, projection number Axle stretched polypropylene films, the excellent in uniformity of the rising height on surface, and there is different projection numbers in the film table.And And if manufacturing capacitor using such biaxial-stretched polypropylene films, insulation breakdown occurs even in high voltage band, The film interlayer spacings required for the Min. dispersed for evaporation metal can be equably kept, thus it is good with self-healing property, Destroy without short circuit as capacitor and capacitor life-span can be remained long-term, safety guarantee can be played consistently so The excellent function of security.

In addition, above-mentioned rising height, projection number, SRz, SRa equivalence can be based on JISB-0601 (1982), strain is used The small slope of formula commercial firm studies made " non-contact three-dimensional fine shape analyzer (ET-30HK) " and " three-dimensional roughness analytical equipment (MODEL SPA-11) " is measured.The detailed content of condition determination etc. is as described later.

Hereinafter, to forming the capacitor of above-mentioned present embodiment biaxial-stretched polypropylene films (following, sometimes referred to as twin shaft Stretched polypropylene films) method illustrate.

As representational method, never add conductive impurity and dislike the electrical characteristics such as breakdown voltage The possibility of change it is low so from the viewpoint of, can use and utilize crystalline modification, obtain projection, the side of surface roughness of target Method.

Here the configuration of surface obtained by crystalline modification is illustrated.The so-called face using crystalline modification forms method, For example, M.Fujiyama, Journal of Applied Polymer Science36, P.985-1048 described in (1988) etc. Like that, it is to carry out the method for surface formation using 2 systems of crystallization possessed by polypropylene, is previously generated by making non-stretched α crystalline substances (monoclinic system, crystal density 0.936g/cm²) system spherocrystal and β crystalline substances (hexagonal crystal system, crystal density 0.922g/cm²) system Spherocrystal, in stretching process, make the β crystalline substances crystalline modification of thermally labile brilliant for α, so as to form bumps on film surface.Pass through we Method obtain concave-convex surface elementary cell due to spherocrystal deformation, therefore the shape sometimes due to projection group and present to be formed For the pit shape of ellipticity, arc-shaped.By the surface configuration that the crystalline modification obtains sometimes through the pit being largely present Shape is formed, and each projection is by connecting into ellipticity, arc-shaped, so as to which pit shape be presented sometimes.

In addition, according to this technology, it is characterized in：Do not formed in the place in the absence of β crystallographic system spherocrystals concavo-convex and become comparison and put down It is smooth.Present the projection group of above-mentioned pit shape with it is biaxial stretch-formed when stretching ratio in length and breadth change than accordingly, in aspect ratio For 1, i.e., isotropic stretching when turn into substantially round shape, as aspect ratio becomes big and flattening.Generally, by gradually biaxial stretch-formed What method obtained is shaped as elliptical shape of the transverse direction (width of film roll) with major axis in film.In addition, the shape according to spherocrystal Into method, the multiple overlapping shapes of variform pit are shown sometimes, and circular arc does not close and is in circlewise sometimes in addition Existing arciform or semiarc shape shape.

, can be with as generating one of method of surface configuration related to above-mentioned defined Pa, Pb in present embodiment The method that core Forming ability is improved using the raw material added with nucleator effect.Make small thereby, it is possible to increase core number Micro crowning is largely present, and reduces relatively flat place (part that projection is not present), is formed uniformly as overall There is the configuration of surface of projection.Such surface is due to densely be formed projection, therefore the above-mentioned present embodiment regulation that is content with very little Surface configuration.

As the raw material with nucleator effect, branched polypropylene can be illustrated.By controlling branched is polyacrylic to add Dosage and film forming condition, so as to control above-mentioned pit shape, therefore as a result, it is possible to generate the double of above-mentioned present embodiment The surface configuration of the characteristic of axle stretched polypropylene films.

The biaxial-stretched polypropylene films of present embodiment preferably comprise the mass % of branched polypropylene 0.05~10.In addition, Here so-called branched polypropylene, it is to have for forming in the polyacrylic carbon atom 10,000 of branched below 5 places The substituted olefine of inside 3 polypropylene.The presence of the substituted olefine of inside 3 can pass through¹The proton ratio of H-NMR spectrum carries out true Recognize.

In order to obtain above-mentioned branched polypropylene, preferably using following methods：By the oligomer with branched structure, gather The method that compound is blended；Length is imported in polypropylene molecule as described in Japanese Unexamined Patent Application 62-121704 publications The method of chain branched structure；Or method etc. as described in No. 2869606 publications of Japanese Patent Publication No..Furthermore, it is possible to for such as Such method for having imported short-chain branch described in Japanese Unexamined Patent Application Publication 2009-542872 publications.As the branched that can be obtained Polypropylene, specifically, Basell societies system " Profax PF-814 ", Borealis societies system " Daploy HMS-PP " can be illustrated.

In addition, from the viewpoint of Film making properties, the polyacrylic melting tension force of branched is preferably in 1cN~30cN model Enclose, be more preferably in 2cN~20cN scope.It is higher to melt tension force, then there have the tendency of the uniformity of rising height to be higher, is easy to (the projection number of per unit area is more) are formed as the surface of densification.If melting tension force is less than 1cN, rising height it is equal Even property is poor, on the other hand, if it exceeds 30cN, then can not keep preferable rising height sometimes.

By containing the mass % of branched polypropylene 0.05~10, so as to by the bosher of the resin sheet of melting extrusion The spherulite size generated in sequence is easier to control small, can suppress the generation of the insulation defect generated in stretching process It is small, the excellent polypropylene screen of proof voltage can be obtained.In addition, although branched polypropylene has the function that α crystalline substance nucleators, If a range of addition, then also it can carry out asperities using crystalline modification and be formed.Thus, with reducing above-mentioned spherocrystal The effect of size is combined with each other, and can be provided the size for the projection group for reducing aftermentioned pit, can be densely be formed, projection Excellent in uniformity, and the biaxial-stretched polypropylene films with the excellent characteristic surface roughness without thick projection.Side chain The polyacrylic content of shape is more preferably 0.05~3 mass %.By making the polyacrylic content of branched be in above range, so as to Windability, proof voltage, which can be obtained, to be improved, the excellent film of element processability, capacitor specific characteristics.

In addition, by adding branched polypropylene, common polyacrylic melt crystallization temperature is about 110 DEG C or so, More than 115 DEG C can be increased on the other hand.That is, due to melt crystallization temperature in the self-healing (self-healing technique) of capacitor Height, therefore safety guarantee is easy to recover, without insulation breakdown, proof voltage improves.That is, dielectric for some reason Caused discharge energy causes the evaporation metal on discharge part periphery to disperse when insulation breakdown occurs for film, now due to part landform Into high temperature, therefore film in itself also melt by part, but is easy to recrystallize immediately because melt crystallization temperature is high, is easy to recover exhausted Edge.If the atmosphere temperature of capacitor is changed into high temperature, it is generally difficult to recrystallize, is not easy to recover insulating properties, but as above institute State by improving melt crystallization temperature, then in insulation breakdown at a high temperature of recrystallize and be easy to carry out, safety can be improved Protection.In addition, by control surface roughness, such as make rough surface, it is ensured that and the interval between film layer, so that insulating properties is extensive Multiple further to become good, proof voltage further improves.

Next, the straight-chain polypropylene included to the biaxial-stretched polypropylene films of present embodiment illustrates.

Straight-chain polypropylene generally uses in packing timber, capacitor in, and preferably cold xylene soluble portions (following CXS) are excellent Elect as below 4 mass %.Here so-called cold xylene soluble portions (CXS), be by sample in warmed-up dimethylbenzene completely it is molten Room temperature is cooled to after solution, poly- third be dissolved in after being separated by filtration by cooling and the undissolved composition separated out in dimethylbenzene Alkene composition, due to the reason such as stereoregularity is low, molecular weight is low, it is believed that equivalent to the composition for being difficult to crystallize.If this The composition of sample is largely contained in resin, then occur sometimes film thermal dimensional stability is poor, the breakdown voltage under high temperature drops Low problem.Therefore, CXS is preferably below 4 mass %, more preferably below 3 mass %, particularly preferably 2 mass % Below.For used straight-chain polypropylene, preferably meet above range, it is also preferred that using copolymer as constituent Film integrally meet above range.In addition, CXS is more few more preferred, but substantial lower limit is 1 mass % or so.

In order to which the polymer that there is CXS with ratio as described above, polypropylene screen is made, raising can be used to be polymerize The method of catalytic activity during thing；The method that the polymer of gained is washed in itself with normal heptane equal solvent or propylene monomer Deng.From the same viewpoint, the polyacrylic unit composition ratio of isotaxy five of straight-chain is preferably more than 0.95, further excellent Elect more than 0.97 as.The polyacrylic knot that the unit composition ratio of isotaxy five is measured for expression by nuclear magnetic resonance method (NMR methods) The index of the stereoregularity of crystalline phase, the numerical value is higher, then crystallinity is higher, and fusing point is higher, the breakdown voltage under high temperature It is higher, therefore preferably.On the upper limit of the unit composition ratio of isotaxy five, without special provision.Structure is found in this wise in order to obtain The high polymer of regularity, the method that will be washed by polymerizeing the toner obtained with normal heptane equal solvent can be illustrated Deng.The more high more preferred but substantial higher limit of the unit composition ratio of isotaxy five is 0.995 or so.

As the straight-chain polypropylene that can be used in present embodiment, from Film making properties aspect, preferred molten flowing Index (melt flow rate (MFR)：MFR 1g/10 minutes~10g/10 minutes (230 DEG C, 21.18N loadings)) are more preferably, it is especially excellent Elect the straight-chain polypropylene of the scope of 2g/10 minutes~5g/10 minutes (230 DEG C, 21.18N loadings) as.In order that melt-flow Index (MFR) is above-mentioned value, can use control mean molecule quantity, the method etc. of molecular weight distribution.

In addition, as straight-chain polypropylene, in addition to being mainly the homopolymer of propylene, the purpose of the present invention is not being damaged In the range of, can be to contain polypropylene copolymer of other unsaturated hydrocarbons as copolymer composition, furthermore, it is possible in the equal of propylene The polypropylene copolymer for containing unsaturated hydrocarbons as copolymer composition is blended with polymers.As such copolymer composition, form and mix The monomer component of mixed thing, can enumerate such as ethene, propylene (in the case of the blend being copolymerized), 1- butylene, 1- amylenes, 3- Methyl-1-pentene, 3-methyl-1-butene, 1- hexenes, 4-methyl-1-pentene, 5- ethyl -1- hexenes, 1- octenes, 1- decene, 1- Dodecylene, vinylcyclohexene, styrene, allyl benzene, cyclopentene, ENB, 5- methyl -2- ENBs etc..Close In the use level of copolymer composition or the blending amount of copolymer, from resistance to insulation breakdown characteristic, dimensional stability aspect, it is copolymerized into The use level divided is preferably smaller than 1mol%, and the blending amount of copolymer is preferably smaller than 10 mass %.

In addition, in such straight-chain polypropylene, in the range of the purpose of the present invention is not damaged, can also contain each Kind of additive, for example, it is crystallization nucleating agent, antioxidant, heat stabilizer, antiseize paste, antistatic additive, anti-blocking agent, filler, viscous Spend conditioning agent, coloring preventing agent etc..

Wherein, the selected of the species and content of antioxidant is important for long-term heat resistance sometimes.It is used as this The antioxidant of sample, it is however preferred to have the antioxidant of the phenol system of sterically hindered property, wherein at least a kind is molecular weight more than 500 HMW type antioxidant.As its concrete example, various antioxidants can be enumerated, preferably for example with 2,6- bis--tertiary fourth Base-paracresol (BHT：Molecular weight 220.4) together and with (the 3,5- di-t-butyl -4- hydroxyls of 1,3,5- trimethyls -2,4,6- three Benzyl) benzene (such as チバガイギー society Irganox (registration mark) 1330：Molecular weight 775.2) or four [methylene -3- (3,5- di-t-butyl -4- hydroxy phenyls) propionic ester] methane (such as チバガイギー society Irganox1010：Molecular weight 1,177.7) etc..The total content of these antioxidants is relative to the scope that polypropylene total amount is preferably 0.03~1 mass %.If Antioxidant is less than 0.03 mass %, then long-term heat resistance is poor sometimes.If antioxidant is more than 1 mass %, due to these Oozing out for antioxidant and cause the adhesion under high temperature, harmful effect is brought to capacitor element sometimes.Preferred content is 0.1~0.9 mass %, particularly preferably 0.2~0.8 mass %.

In present embodiment, in the range of the purpose of the present invention is not violated, crystallization nucleating agent can be added.As above institute State, the crystallization nucleating agent effect that branched polypropylene itself has α brilliant or β is brilliant, but further preferably add the α crystalline substances of other species into Core agent (dibenzylidene sorbitol class, sodium benzoate etc.), β crystalline substances nucleator (1,2- hydroxy stearic acids potassium, magnesium benzoate, N, N '- The acid amides based compounds such as dicyclohexyl -2,6- aphthalimides, quinacridone based compound etc.) etc..But present embodiment In, by adding these crystallization nucleating agents, there are the surface roughness etc. for being difficult to obtain target, the drop of specific insulation under high temperature It is low that dysgenic possibility is also brought to electrical characteristic, as content, it is sometimes preferred to preferably smaller than 0.1 mass %, enter one Step is preferably not add substantially.

In addition, the glossiness on the biaxial-stretched polypropylene films surface of present embodiment, from film thickness be 1~3 μm very Thin film thickness, and require that high proof voltage sets out, preferably 110~135% scope, more preferably 120~130%. That is, in order that glossiness reduces, it is meant that improve the density of the light scattering on film surface, i.e. make the bumps on film surface fine and close, often The projection number increase of unit area, roughness density become big.If however, make glossiness decrease below 110%, although The impregnation of liquid becomes good, but due to fine and close projection formation thus rising height, the increase of projection number, so as to dash forward sometimes Airtrapping amount between rising increases, and is easy to slide between film layer, the windability deterioration of element, and film wound into rolls is become into difficult, this Outer proof voltage reduces.On the other hand, if glossiness is more than 135%, occur to be not easy to slide between film layer sometimes, be shaped to The capacitor element of flat becomes difficult, or the dustability of sufficient film interlayer spacings, evaporation metal etc. can not be maintained to deteriorate, The problems such as safety guarantee of capacitor, self-healing property reduce.In addition, if glossiness is 120~130%, then element is windability Improve with the balance of proof voltage, safety guarantee, therefore more preferably.More preferably 123~127%.

In addition, (determination method is according to JIS-C2330 (1995) for the ash content of the biaxial-stretched polypropylene films of present embodiment 6.3.5 be preferably) below 50ppm (quality criteria, same as below), more preferably below 30ppm, particularly preferably 20ppm with Under.If such ash content is excessive, the resistance to insulation breakdown characteristic of film reduces, and insulation breakdown sometimes is made in the case of capacitor Intensity decreases.In order that ash content is within the range, it is important using the few raw material of catalyst residue, can uses from film When extrusion system pollution also strongly reduce etc. method, such as make the precipitation time spend more than 1 hour, actually starting The methods of path is fully washed with polymer before film.In addition, ash content is more few more preferred, but substantial lower limit For 10ppm or so.

The biaxial-stretched polypropylene films of present embodiment are preferably used as capacitor dielectric film, but for the class of capacitor Type does not limit.Specifically, can be paper tinsel wound capacitor, metal evaporation membrane capacitance from the viewpoint of electrode composition It is any, be further preferably used in containing be soaked with insulating oil oil immersed capacitor, completely without using the dry-type capacitance of insulating oil Device.Can be takeup type, or laminated type in addition, from the viewpoint of shape.However, from the film of present embodiment Characteristic is set out, and is particularly preferably used as metal evaporation membrane capacitance.

In addition, the usual surface energy of polypropylene screen is low, it is difficult stably to implement metal evaporation.Accordingly, with respect to present embodiment Biaxial-stretched polypropylene films, from the good purpose of metal adhesion is made, be preferably surface-treated in advance.So-called surface Processing, specifically, can illustrate Corona discharge Treatment, corona treatment, aura processing, flame treatment etc..Usual polypropylene The surface wettability tension force (determination method is according to JIS K-6768 (1995)) of film is 30mN/m or so, by these surface treatments, is made Wetting tension is 37~50mN/m, preferably 39~48mN/m or so, and excellent in adhesion with metal film, safety guarantee also becomes Obtain well, therefore preferably.

The biaxial-stretched polypropylene films of present embodiment are by using the raw material that can bring above-mentioned characteristic, under prescribed conditions It is biaxially stretched to obtain., can also be simultaneously double by inflation simultaneously biaxial drawing method, tentering as biaxial stretch-formed method The either method of axle pulling method, tentering gradually biaxial stretching process obtains, wherein, from control film stability, thickness evenness, Set out in terms of the surface configuration of film, it is preferred to use tentering gradually biaxial stretching process.

Next, the system to the biaxial-stretched polypropylene films of present embodiment using tentering gradually biaxial stretching process below The method of making illustrates, but is not necessarily limited to this.

First, filter is passed through in straight-chain acrylic resin to provide ratio blending branched polypropylene and melting extrusion After crossing filter, in 220~280 DEG C of temperature from slit-shaped die extrusion, make its solidification on cooling drum, obtain non-stretched Film.

As the adhesion method with cooling drum, the closely sealed side of electrostatic application method, the surface tension that make use of water can be used Either method in method, air knife method, pressure roller method, water in casting method etc., preferably flatness are good and can to carry out surface thick The air knife method of rugosity control.

In air knife method, as the method for the projection on control film surface, as prior art, patent document 3, specially can be enumerated The control method of the air temperature control method of air knife is utilized described in sharp document 4 like that.However, carried out merely with air knife method When surface roughness controls, although a certain degree of projection can be controlled to be distributed, it is difficult to obtain the film with present embodiment The polypropylene screen of projection distribution in table.

In the biaxial-stretched polypropylene films of present embodiment, in order that occurring desired rising height and institute's phase in film table The projection number of prestige, non-stretched is set to be sealed at cooling drum, while the circle of the ＞ of ＜ 1 control cooling drums in set point of temperature by air knife Circular velocity；The ＞ of ＜ 2 control the temperature hold-time of drum surface side and non-drum surface side, control the brilliant growing amounts of the β in film table, size, Preheating temperature, the peripheral speed of pre- hot-rolling, roll gap (nip) pressure of pre- hot-rolling of the ＞ of ＜ 3 controls untill stretching in addition Power, nip temperature；Nip pressure, the nip temperature in the ＞ restrained stretchings portions of ＜ 4 are important.Here, so-called temperature hold-time, Refer to the time that unstretching film contacts with cooling drum.

By changing the temperature hold-time in film table, so as to control the brilliant growing amounts of the β on film surface, projection high Degree.For example, the temperature easily generated with the face that cooling drum contacts due to being maintained at β crystalline substances, therefore the generation quantitative change of β crystalline substances is more, size Diminish.The temperature that β crystalline substances easily generate is not maintained at it because the bulging heat of cooling transfers heat in film with the cooling face that contact of drum on the contrary Degree, therefore compared with chill roll contact surface, shortened in the retention time for the temperature that β crystalline substances easily generate, growing amount brilliant β tails off, Rising height, fibril size uprise.

In addition, as changing to the method for the heat provided in film table, as described in patent document 5, have and stretching During preceding preheating, control and method of the time of contact for the roller that each face contacts etc. in table.However, in pole as the present embodiment During the film of its thin film, because the heat-transfer rate inside film is fast, therefore only control with when time of contact of chill roll, preheating It is insufficient for control projection number with the time of contact of each roller.

Therefore, the temperature of the pre- hot-rolling contacted by change with one side, nip pressure, nip temperature, so as to control one side Will stretch before film temperature, even extremely thin film as the present embodiment, can also be advantageously controlled desired Surface roughness, rising height, number.Thus, due to can independently control the surface roughness in film table, therefore can Form the surface of target.In addition, nip pressure, nip temperature by changing extension section in the lump, so as to control accuracy be easy into One step improves.

In refrigerating work procedure after extrusion, in order to efficiently generate β crystalline substances, preferably turn into maximum in formation efficiency brilliant β Resin temperature maintains the stipulated time.Here, it is preferably 70~135 DEG C to cool down bulging temperature, more preferably 80~120 DEG C, Particularly preferably 85~110 DEG C of scope.In addition temperature hold-time, preferably more than 1.5 seconds, particularly preferably 2.0 are used as More than second.

Next, making the unstretching film biaxial stretch-formed, make its biaxial orientation.First, by unstretching film by between pre- hot-rolling, Film is preheated.As the temperature of preheating part now, preferably 120~140 DEG C.Now, contacted with the A surface sides of film pre- The temperature of hot-rolling is preferably 130~140 DEG C.In addition, on the nip pressure of the preheating part contacted with A faces, preferably 0.25~ 0.55MPa, more preferably 0.35~0.45MPa.Furthermore it is preferred that the nip temperature of the preheating part contacted with A surface sides is preferably 100 ~140 DEG C.More preferably 110~130 DEG C.

So, by controlling the temperature and pressure of the roll gap contacted with A surface sides, so as to control the prominent of the A faces of only film Rise.In addition, in the case where the temperature change according to preheating part deteriorates conveying due to fold etc., by adjusting between pre- hot-rolling Peripheral speed eliminate.Peripheral speed preferably forms 0.1~3.0% speed difference in front and rear roller.In addition, justified by setting Circular velocity is poor, then the adaptation of film and roller improves, and can easily control film temperature.Therefore, by making difference more excellent Elect 1.0~2.5%, more preferably 1.5~2.0% as, become easy so as to the control of film temperature.

Next, the brilliant fusings of β in the roll temperature of the extension section as length direction, preferably unstretching film, in film table Face forms 130 DEG C~160 DEG C of temperature of projection.More preferably 135 DEG C~155 DEG C, particularly preferably 140 DEG C~150 ℃.If the roll temperature of extension section, more than 160 DEG C, film fuses with roller, film rupture occurs sometimes.If opposite roll temperature is less than 130 DEG C, then inequality, or the brilliant projections non-fusible and that film surface can not be formed of β are stretched sometimes.

In addition, in stretch zones, preferably heat is assigned by pharoid.Radiant heating is utilized in stretch zones The heat that device is carried out assigns the heat turned into when being contacted with the surface of roller and assigns different films non-contacting heat imparting, Neng Gouzhi Connect and accurately the projection of control surface is formed.Therefore, the biaxial-stretched polypropylene films of present embodiment can by with Conventional assigns heat in the lump using roller to film, by controlling non-contacting heat to assign, to stretching roll gap side it is additional equal Even heat, to form the projection distribution in defined film table.Here, the heat carried out using pharoid assigns preferred pair A Surface side is carried out.In addition, the output of pharoid, in the same manner as the heat imparting of roller, preferably β is brilliant to be melted and in film surface shape Into 1.5kW~13.0kW of projection.More preferably 2.0kW~11.0kW, particularly preferably 2.5kW~10.5kW.If The output of pharoid melts more than 13.0kW, then film, it is prone to which film ruptures.If the output of opposite pharoid is small In 1.5kW, then film rupture, the protrusion of surface for being assigned using pharoid heat side is diminished, and is unable to shape film formation surface sometimes Desired projection distribution.

In the biaxial-stretched polypropylene films of present embodiment, on the stretching ratio of length direction, in order to aid in β is brilliant to melt Change, preferably vertical 4.0 times~5.5 times of stretching ratio.More preferably 4.3 times~5.2 times.Due to by stretching and film surface Projection stretching, extension, can be with control projection size therefore by restrained stretching multiplying power.If vertical stretching ratio is higher than 5.5 times, film It is easy to be broken, film becomes difficult.In addition, if stretching ratio is low, the projection size on film surface diminishes sometimes, and tensile strength becomes It is low.If stretching ratio is less than 4.0 times, obtains desired projection size and become difficult, damage proof voltage sometimes, safety is protected Barrier property.

In the biaxial-stretched polypropylene films of present embodiment, be quenched immediately after the stretching of the length direction of film for It is important for stably control projection distribution.That is, preferably after length direction just stretches, it is quenched to 30~50 DEG C.Pass through Quenching is to 30~50 DEG C, so as to stop the brilliant fusings of β, the rising height on the film surface that can keep being formed during stretching, Number.In the case where chilling temperature is higher than 50 DEG C, because the brilliant fusings of β do not stop, therefore it can not keep what is formed by stretching The projection distribution on film surface, is not easy to obtain rising height, the number on the film surface of present embodiment sometimes.In addition, in cooling temperature In the case that degree is less than 30 DEG C, because the solidification of film is promptly carried out, become big it is therefore possible to the change in size of film, film becomes It is unstable.As method of quenching, there is the method using chill roll, air.

After length direction stretching, the stretched film is directed into stenter, in 150~170 DEG C of temperature in width 5~15 times are stretched to, 2~20% relaxation is then assigned in width, at the same it is fixed in 140~170 DEG C of temperature progress heat Shape.After heat setting, in order that the cementability of evaporation metal is good, the face that can be deposited by the implementation to stretched film, in sky Corona discharge Treatment is carried out in gas, in nitrogen, in carbon dioxide or in their mixed gas, so as to obtain desired twin shaft Stretched polypropylene films.

In present embodiment, metal film is set on above-mentioned biaxial-stretched polypropylene films surface and method that metalized film is made It is not particularly limited, for example, it is preferable to using at least one side of the biaxial-stretched polypropylene films to present embodiment, further according to need Will be to two sides, AM aluminum metallization and the method for being set to the metal films such as the aluminium-vapour deposition film of the internal electrode of membrane capacitance.Now, may be used also So that other metal ingredients such as nickel, copper, gold, silver, chromium and zinc to be simultaneously or sequentially deposited with aluminium.Further, it is also possible in evaporation film It is upper that with oil etc., protective layer is set.

On the thickness of metal film, from the electrical characteristic and self-healing property aspect of membrane capacitance, preferably 20~100nm Scope.In addition, according to the reasons why same, the sheet resistance value of metal film is preferably 1~20 Ω/ scope.Sheet resistance Value can be by used metal kind and film thickness monitoring.In addition, the determination method of sheet resistance is as described later.

, can be as needed in present embodiment, after metal film is formed, metalized film is carried out always in specific temperature Change is handled, or is heat-treated.In addition, for insulation or other purposes, at least one side of metalized film can also be implemented poly- The coating of phenylate etc..

The metalized film being achieved in that can obtain membrane capacitance using various methods come lamination or winding.If illustrate The preferable manufacture method of convoluted membrane capacitance, then it is as follows.

In a face vacuum evaporated aluminium (evaporation process) for the biaxial-stretched polypropylene films of present embodiment.Now, it is deposited into Strip with the edge part moved towards in film length direction.Next, in central and each edge part of each steam plating part on surface Sword is inserted to cut (cutting action) in center, and a side on surface, which is made, has the ribbon wound spool at edge.Use left or the right side Side has the ribbon wound spool at edge, and by the spool of left hand edge and right hand edge, each 1 overlapping 2 are wound so that in width Spend direction evaporated segment to stretch out from edge part, obtain coiling body (element volume process).Core is extracted from the coiling body to be suppressed, Outer electrode is made in the spraying plating of both ends of the surface metalling, the welding lead in metallising, it is hereby achieved that convoluted film Capacitor.The purposes of membrane capacitance prevents from using throughout vehicle with, household electrical appliances with (TV, refrigerator etc.), general noise, automobile using is (mixed Close power car, motorized window, wiper etc.) and many-side, the membrane capacitance of present embodiment such as power supply use can also be suitable for These purposes.

The assay method of the characteristic value of biaxial-stretched polypropylene films in present embodiment and the evaluation method of effect are such as It is lower described.

(1) film thickness t1 (μm)

According to the 7.4.1.1 of JIS C-2330 (2001), micrometer method thickness is determined.

(2) glossiness (gloss)

According to JIS K-7105 (1981), スガ testing machine Co. Ltd. system numeral varied-angle glossmeter UGV-5D will be used, The average value of 5 point datas measured under conditions of 60 ° of incidence angle, 60 ° of acceptance angle is set to glossiness.

(3) melt flow rate (MFR) (MFR)

According to JIS-K7210 (1999), it is measured with 230 DEG C of measurement temperature, loading 21.18N.

(4) tension force (MS) is melted

Device based on the MFR measure shown in JIS-K7210 (1999) is measured.Use Toyo Seiki melt Force tester, the polypropylene of measure object is heated to 230 DEG C, melt polypropylene is discharged with extruded velocity 15mm/ minutes, made Into strands, determine the strands with the tension force during speed drawings of 6.5m/ minutes, be set to melt tension force.

(5) melt crystallization temperature (DEG C)

Using セイコー societies RDC220 differential scanning calorimetry (DSC)s, it is following it is following under the conditions of be measured.

The modulation ＞ of ＜ samples

Corpse or other object for laboratory examination and chemical testing 5mg is enclosed to the aluminium dish of measure.It is in addition, appropriate in the case where implementing metal evaporation etc. to film Remove.

＜ determines ＞

Make film melting, recrystallization according to the step of following (a) → (b).Measure 3 times, by the peak that the Tmc is observed Average value is set to melt crystallization temperature.

(a) operation 30 DEG C → 280 DEG C (20 DEG C/min of programming rates) for the first time

(b) 30 DEG C are cooled to 20 DEG C/min after Tmc is kept for 5 minutes at 280 DEG C

(6) the unit composition ratio (mmmm) of isotaxy five

Sample is dissolved in solvent, used¹³C-NMR, the unit composition ratio of isotaxy five is obtained using following condition (mmmm) (bibliography：The analytical chemistry meeting macromolecule analysis and research of Japan of new edition macromolecule analysis handbook civic organization are talked sincerely Nineteen ninety-five P609~611 can be compiled).

A. condition determination

Device：Bruker societies system, DRX-500

Determine core：¹³C core (resonant frequencies：125.8MHz)

Determine concentration：10 weight %

Solvent：Benzene/deuterated o-dichlorohenzene=mass ratio 1:3 mixed solutions

Measurement temperature：130℃

Rotary rpm：12Hz

NMR coupons：5mm is managed

Pulse width：45°(4.5μs)

Pulse-recurrence time：10 seconds

Data point：64K

Convert number：10,000 times

Mode determination：complete decoupling

B. analysis condition

LB (the spectral line broadening factor, line broadening factor) is set to 1.0 carry out Fourier transforms, by mmmm Peak is set to 21.86ppm.Using WINFIT softwares (Bruker societies system), peak division is carried out.Now, since the peak of highfield side Peak division is carried out in the following manner, further carries out the automatic Fitting of accompanying software, carries out the optimization of peak division, then will Mmmm and ss (mmmm spinning side band peak) the total of peak point rate is set to the unit composition ratio (mmmm) of isotaxy five.

In addition, measure is carried out 5 times, it is averaged value and is set to the unit composition ratio of isotaxy five.

Peak

(a)mrrm

(b) (c) rrrm (being split into 2 peaks)

(d)rrrr

(e)mrmm+rmrr

(f)mmrr

(g)mmmr

(h) ss (mmmm spinning side band peak)

(i)mmmm

(j)rmmr

(7) internal 3 substituted olefine numbers (in carbon atom 10,000)

Sample is dissolved in solvent, used¹H-NMR, the number of internal 3 substituted olefines is obtained using following condition.

A. condition determination

Device：JEOL ECX400P type nuclear magnetic resonance devices

Determine core：¹H core (resonant frequencies：500MHz)

Determine concentration：2 weight %

Solvent：Deuterated o-dichlorohenzene

Measurement temperature：120℃

Pulse width：45°

Pulse-recurrence time：7 seconds

Convert number：512 times

Mode determination：non decoupling

B. analysis condition

The chemical shift 7.10ppm of o-dichlorohenzene is set to benchmark, by the signals assignment in 5.0~5.2ppm regions in inside The proton of 3 substituted olefines, by itself and proton ratio of the integration of 0.5~2.0ppm bandwidth signals than obtaining internal 3 substituted olefines.

(8) cold xylene soluble portions (CXS)

After polypropylene screen sample 0.5g is dissolved in boiling xylene 100ml and let cool, in 20 DEG C of Water Tank with Temp.-controlled Recrystallize 1 hour, then carry out the polypropylene-based components utilising liquid chromatography for being dissolved in filtered fluid quantitative (X (g)).Make Obtained with sample 0.5g smart value (X0 (g)) using following formula.

CXS (quality %)=(X/X0) × 100

(9) center line average roughness (SRa), 10 mean roughness (SRz), Pa, Pb

By JIS B-0601 (1982), using Kosaka Laboratory Ltd.'s system, " non-contact three-dimensional fine shape determines Instrument (ET-30HK) " and " three-dimensional roughness analytical equipment (MODELSPA-11) " are measured.It is determined as and is repeated in length direction 10 times, its average value is taken, obtains center line average roughness (SRa), 10 mean roughness (SRz), total projection number.

On 1 time measure detailed conditions and data processing, as described below.

The projection number detected by said determination instrument, export short transverse every 50nm (50nm, 100nm, The number in each region 150nm).

(a) total projection number Pa, Pb (unit：Individual/0.1mm²)

Total projection number represents to detect the width shown in the project with condition determination, length direction sampling interval Projection number be converted into every 0.1mm²Number obtained by value it is all total obtained by value.

Specifically, it is total testing number in each region of the short transverse exported by said determination instrument.

Condition determination

Aspect of measure processing：In aspect of measure vacuum evaporated aluminium, using eyes with non-contact method.

Determine direction：The width of film

Width feed speed：The 0.1mm/ seconds

Measurement range (width × length direction)：1.0mm×0.249mm

The reference plane of short transverse size：LOWER (downside)

Width sampling interval：2μm

Length direction sampling interval：10μm

Length direction samples radical：25

Cut-off：The 0.25mm/ seconds

Width enlargement ratio：200 times

Length direction enlargement ratio：20,000 times

Rise and fall, roughness cut-off：Nothing

Assay method

Special specimen holder is used in film measure.Specimen holder is removably 2 pieces of metallic plates that circular port is vacated at center, Clamp sample therebetween and pull the surrounding that film makes it be installed to specimen holder, so as to which film be fixed, enter for the film of central circular portion Row roughness determines.

Measurement result：Data processing

The example of the measurement result obtained by the above method is shown in Table 1.

[table 1]

Each parameter can be read as described below by table 1.

(10) film resistance of metal film

Metalized film is cut into the rectangle of length direction 10mm, width overall width (50mm), as sample, passed through 4 terminal methods, the resistance of the metal film between width 30mm is determined, the measured value of gained is multiplied by into measure width (10mm) removes again With interelectrode distance (30mm), film resistance (sheet resistance) is calculated.(unit：Ω/□)

(11) film breakdown voltage (V/ μm)

According to JIS C2330 (2001) 7.4.11.2 B methods (plate electrode method), average value is obtained, divided by the sample determined The micrometer method film thickness (μm) (above-mentioned) of product, with V/ μm of statement.

(12) the element processability (element retracting rate) when capacitor manufactures

It is true using ULVAC systems in the one side by each embodiment described later and the biaxial-stretched polypropylene films of comparative example acquisition Empty evaporator vacuum evaporated aluminium makes film resistance turn into 8 Ω/sq.Now, it is deposited into the edge part moved towards in length direction Strip (the width 39.0mm of steam plating part, the width 1.0mm of edge part repetition).Next on central and each side of each steam plating part Sword is inserted to cut, to have the overall width 20mm at 0.5mm edge banding that volume is made in left or right in the center of edge Around spool.By the spool of the left hand edge of the spool of gained and right hand edge, each 1 overlapping 2 are wound, to be steamed in width 0.5mm is stretched out in plating part from edge part, obtains the μ F of static capacity about 10 coiling body.Element winding has used all rattan making made KAW-4NHB。

During the manufacture of above-mentioned capacitor, start to winding to terminate with visual observation winding, the situation that fold will occur, offset Be set to unqualified, by be not defective work number it is expressed as a percentage relative to the overall ratio of manufacture number, be set to processability Index (hereinafter referred to as element retracting rate).Element retracting rate is more high more preferred.Good "○" is set to by more than 95%, will be less than 95% and more than 80% is set to " △ ", will be set to bad "×" less than 80%."○" or " △ " are level that can be practical.

(13) evaluation of capacitor specific characteristics is deposited

To the biaxial-stretched polypropylene films by each embodiment described later and comparative example acquisition, ULVAC vacuum evaporations are utilized Machine AM aluminum metallization, it is 8 Ω/sq to make film resistance, is imposed with being provided with the so-called T-shaped of edge part in the direction vertical with length direction The evaporation pattern of third edge pattern, obtain width 50mm evaporation spool.

Then, made element volume machine (KAW-4NHB) is made using all rattans using the spool to be rolled up capacitor element Around implementing metallising, then, the temperature at 105 DEG C implements the heat treatment of 10 hours under reduced pressure, installs lead, makes electricity Container component.The static capacity of capacitor element now is 5 μ F.

Using the capacitor element being achieved in that 10, apply 500VDC voltage to capacitor element at normal temperatures, Application voltage is increased with 50VDC/1 minutes stepwise after 10 minutes under the voltage, repeat the operation, carry out So-called ladder rises (step up) experiment.The static capacity change of measure now, draws, the static capacity is turned on the diagram 70% voltage divided by micrometer method film thickness (above-mentioned) of initial value, the evaluation index of proof voltage is set to, by more than 300V/ μm It is set to the level that can be used.In addition, in the high voltage capacitor purposes assumed, the evaluation index of proof voltage is preferably More than 470V/ μm.In addition, rising voltage until static capacity is reduced to less than 10% relative to initial value, then dismounting is electric Container component, the state of destruction is studied, evaluates safety guarantee as described below.

◎：Component shape is unchanged, does not observe the destruction of insertion shape.

○：Component shape is unchanged, it was observed that the insertion shape within 10 layers of film destroys.

△：Confirm component shape change or observe that the insertion shape more than 10 layers destroys.

×：Component shape destroys.

Use with being had no problem during ◎, can be used according to condition when zero.△, × when produce problem in practical use.

Embodiment

Hereinafter, the present invention is explained by embodiment.In addition, characteristic is measured by the above method.

(embodiment 1)

It is 0.985 in the unit composition ratio of isotaxy five, melt flow rate (MFR) (MFR) is the straight-chain of 2.6g/10 minutes In acrylic resin (Borealis societies system " Borclean (registration mark) "), internal 3 substituted olefine numbers are blended relative to carbon It is 3 branched acrylic resin (Borealis societies system " Daploy HMS-PP ") 0.5 mass % in 10,000, atom, Supply to the extruder of 250 DEG C of temperature, in 250 DEG C of from T-shaped slot die sheet melting extrusions of resin temperature, by the molten sheet Rouse and cool and solidify in the cooling for being held in 90 DEG C of diameter 1m, obtain unstretching film.Retention time on chill roll is 2.5 Second.Then, the roller contacted with unstretching film A faces and the side of roller two contacted with unstretching film B faces have carried out pre- at 140 DEG C Heat.Further, in the roll that the A surface sides with film contact, by being passed through steam under pressure, the surface temperature for making roll is 130 DEG C. In addition, nip pressure is set to 0.50MPa.Then pass through between being held in 145 DEG C of temperature and being provided with the roller of difference Film, stretched again in length direction with stretching ratio 4.5.In addition, added in stretch zones with exporting 10.0kW using radiation Hot device additional heat, is stretched.Afterwards at once between 35 DEG C of roller is held in by film, it is quenched.

Then the film is imported into stenter, 10 times of stretchings is carried out in width in 158 DEG C of temperature, then in width side To the relaxation of imparting 6%, while it is heat-treated at 155 DEG C, is then cooled down, obtains the twin shaft that film thickness is 2.5 μm Stretched polypropylene films.Further to the surface of film with 25Wmin/m²Processing intensity carried out in an atmosphere at corona discharge Reason.

Proof voltage when capacitor being made by the characteristic for the biaxial-stretched polypropylene films being achieved in that and by the film is (exhausted Edge breakdown voltage) and element processability (element retracting rate) be shown in table 2,3,4.As shown in table 2,3,4, on by embodiment 1 Capacitor made of the biaxial-stretched polypropylene films being related to, proof voltage, safety guarantee are all excellent.

[table 2]

[table 3]

[table 4]

(embodiment 2)

In the preheating procedure of unstretching film, the roller contacted with film B faces is set to 120 DEG C, and the roller contacted with film A faces is set to 140 DEG C, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.The characteristic of the film of gained is shown in table 2nd, in 3,4.

(embodiment 3)

Pharoid output is set to 7.0kW, in addition, is filmed similarly to Example 1, obtains 2.5 μ M film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 4)

Make to rouse in the cooling for being held in 85 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.By the characteristic of the film of gained It is shown in table 2,3,4.

(embodiment 5)

Make the cooling in the diameter 1m for being held in 100 DEG C in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Cooled and solidified on drum, and the roll temperature contacted in the preheating procedure of unstretching film with film B faces is set to 125 DEG C, is contacted with film A faces Roller be set to 135 DEG C, in addition, be filmed similarly to Example 1, obtain 2.5 μm of film.By the spy of the film of gained Property is shown in table 2,3,4.

(embodiment 6)

In the preheating procedure of unstretching film, the roller contacted with film B faces is set to 120 DEG C, and the roller contacted with film A faces is set to 130 DEG C, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.The characteristic of the film of gained is shown in table 2nd, in 3,4.

(embodiment 7)

The output of pharoid is set to 13.0kW, in addition, is filmed, obtains similarly to Example 1 2.5 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 8)

In the preheating procedure of unstretching film, the roller surface temperature contacted with film A surface sides is set to 140 DEG C, in addition, It is filmed similarly to Example 1, obtains 2.5 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 9)

When unstretching film is stretched in length direction, the roll temperature for being provided with difference is held in 150 DEG C, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.By the characteristic of the film of gained be shown in table 2, 3rd, in 4.

(embodiment 10)

When unstretching film is stretched in length direction, the roll temperature for being provided with difference is held in 140 DEG C, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.By the characteristic of the film of gained be shown in table 2, 3rd, in 4.

(embodiment 11)

Make to rouse in the cooling for being held in 88 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, and the output of pharoid are set to 10.5kW, and horizontal draft temperature is set to 160 DEG C, in addition, with reality Apply example 1 to be similarly filmed, obtain 3.0 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 12)

Make to rouse in the cooling for being held in 89 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, and the output of pharoid are set to 10.5kW, and horizontal draft temperature is set to 159 DEG C, in addition, with reality Apply example 1 to be similarly filmed, obtain 2.8 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 13)

Make to rouse in the cooling for being held in 92 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, and the output of pharoid are set to 9.5kW, in addition, are filmed similarly to Example 1, obtain 2.0 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 14)

Make to rouse in the cooling for being held in 93 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, and the output of pharoid are set to 9.0kW, and horizontal draft temperature is set to 157 DEG C, in addition, with reality Apply example 1 to be similarly filmed, obtain 1.5 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(embodiment 15)

Make to rouse in the cooling for being held in 94 DEG C of diameter 1m in 250 DEG C of molten sheets for having carried out melting extrusion of resin temperature Upper cooling and solidifying, and the output of pharoid are set to 8.0kW, and horizontal draft temperature is set to 157 DEG C, in addition, with reality Apply example 1 to be similarly filmed, obtain 1.2 μm of film.The characteristic of the film of gained is shown in table 2,3,4.

(comparative example 1)

The roll for making roll be no temperature control device, in addition, operates, obtains 2.5 similarly to Example 1 μm film.The characteristic of the film of gained is shown in table 2,3,4.

(comparative example 2)

Branched polypropylene is not added, in addition, is filmed similarly to Example 1, obtains 2.5 μm of film. The characteristic of the film of gained is shown in table 2,3,4.

(comparative example 3)

Using the resin of embodiment 1, after extruding similarly to Example 1, the molten sheet is being held in 60 DEG C of diameter Cooled and solidified on 1m cooling drum, obtain unstretching film.Retention time on chill roll is 2.0 seconds.Then, it is this is non-stretched Film is slowly preheated using 130 DEG C of pre- hot-rolling, by film between the roller of difference is provided with, with 4.6 times of stretching ratio Stretched in length direction.Now, work roll cooling does not have the roll of temperature control device, and nip pressure is set to 0.50MPa.Draw Stretch in region and use pharoid additional heat to export 3.5kW, stretched.The process later on vertical stretching, with Embodiment 1 is similarly implemented, and obtains the film of 2.5 μm of thickness.

(comparative example 4)

Using the resin of embodiment 1, after extruding similarly to Example 1, the molten sheet is being held in 70 DEG C of diameter Cooled and solidified on 1m cooling drum, obtain unstretching film.Retention time on chill roll is 3.0 seconds.Then, it is non-stretched with this The temperature of the roller of the A surface sides contact of film is set to 140 DEG C, and the temperature of the roller contacted with B surface sides is set to 130 DEG C and preheated, and is protecting It is held in 148 DEG C of temperature and is provided between the roller of difference by film, is drawn again in length direction with stretching ratio 4.6 Stretch.Now, work roll cooling does not have the roll of temperature control device, and nip pressure is set to 0.50MPa.With output in stretch zones 10.5kW uses pharoid additional heat, is stretched.The process later on vertical stretching, similarly to Example 1 Implement, obtain the film of 2.5 μm of thickness.

(comparative example 5)

In the preheating procedure of unstretching film, two sides of the roller contacted with film A faces and the roller contacted with B faces are set to 150 DEG C, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.By the characteristic of the film of gained be shown in table 2, 3rd, in 4.

(comparative example 6)

Without using pharoid, in addition, it is filmed similarly to Example 1, obtains 2.5 μm of film.Will The characteristic of the film of gained is shown in table 2,3,4.

Industry utilizability

Biaxial-stretched polypropylene films of the present invention, metalized film can be used in manufacturing capacitor, can particularly fit Share in membrane capacitance of the manufacture as automobile component.

Claims

1. a kind of capacitor biaxial-stretched polypropylene films, it is the capacitor biaxial-stretched polypropylene films that two sides has projection, Thickness t1 is 1~3 μm, the unit of the thickness t1 for μm, a film surface is being set to A faces, it is full when another side is set into B faces Whole following formula (1)~(4) of foot,

|Pa-Pb|≥200 (1)

0.350≤Pa/SRzA≤0.700 (2)

500nm≤SRzA≤1,200nm (3)

50nm≤SRzB ＜ 500nm (4)

Wherein, Pa represents A faces per 0.1mm²The number of existing projection, Pb represent B faces per 0.1mm²Of existing projection Number, SRzA represent 10 mean roughness in A faces, and SRzB represents 10 mean roughness in B faces.

2. capacitor biaxial-stretched polypropylene films according to claim 1, the center line average roughness SRaA in A faces are More than 25nm and below 45nm.

3. capacitor biaxial-stretched polypropylene films according to claim 1 or 2, the center line average roughness in B faces SRaB is more than 10nm and below 25nm.

4. a kind of metalized film, the capacitor biaxial-stretched polypropylene films described in its any one in claims 1 to 3 are extremely It is few to be simultaneously provided with metal film.

5. metalized film according to claim 4, the sheet resistance of metal film is 1~20 Ω/.

6. a kind of membrane capacitance, it use the metalized film described in claim 4 or 5.